1. Field of the Invention
The present invention relates to apparatus for handling a web of material made up of individual tows, and more particularly to apparatus for removing a fill yarn which is alternately interlaced with the web across the width thereof so as to hold the individual tows thereof together for prior processing.
2. History of the Prior Art
It is known to weave or interlace a length of fill yarn alternately back and forth across the width of a web of individual tows disposed in side-by-side relation across the width of the web so as to hold the tows in place for processing thereof. During the carbonization of filaments of PAN or similar material, for example, it is common practice to weave a length of fill yarn back and forth across the width of the web prior to carbonization so as to hold the individual tows of filaments in place as part of an integral woven structure. The resulting web tends to minimize or avoid damage of the delicate filaments as the web is advanced over rollers and other equipment during the carbonization of the filaments. Apparatus for inserting the fill yarn to form such a web is described in U.S. Pat. No. 4,173,990 of Langlois et al, issued Nov. 13, 1979 and commonly assigned with the present application.
Upon completion of carbonization or other processing requiring the presence of the fill yarn, it is usually necessary that the fill yarn be removed so that other processing or ultimate utilization of the tows comprising the web can take place. This is usually accomplished using one of several techniques involving a substantial amount of manual labor. In the most common of such techniques the different lengths of fill yarn extending across the width of the web are cut at approximately their midpoints by scissors or other appropriate cutting instruments as the web is advanced through a work area. Following that, the loops of fill yarn at the opposite edges of the web are grabbed and pulled by hand to remove the cut pieces of the fill yarn. Such process is relatively slow and tedious. It typically requires the full time and attention of two people, one standing on each side of the web which is typically three to four feet or more in width. At the same time the process is relatively slow because of the time required to hand cut and hand remove the fill yarn. Optimum speed for such a process is usually about five feet per minute of web advance.
Accordingly, it would be desirable to be able to provide an improved technique and improved apparatus for removing fill yarn from a web of tows. It would be especially advantageous to be able to remove the fill yarn automatically by machine so as to eliminate the need for manual labor and require only occasional operator supervision. It would furthermore be advantageous to be able to remove the fill yarn from a web of tows at speeds greatly in excess of those realizable with present manual techniques.